HttpURLConnection和HTTPClient的比较,以及使用规则

1.概念      

      HTTP 协议可能是现在 Internet 上使用得最多、最重要的协议了，越来越多的 Java 应用程序需要直接通过 HTTP 协议来访问网络资源。在 JDK 的 java.net 包中已经提供了访问 HTTP 协议的基本功能：HttpURLConnection。但是对于大部分应用程序来说，JDK 库本身提供的功能还不够丰富和灵活。

      除此之外，在Android中，androidSDK中集成了Apache的HttpClient模块，用来提供高效的、最新的、功能丰富的支持 HTTP 协议工具包，并且它支持 HTTP 协议最新的版本和建议。使用HttpClient可以快速开发出功能强大的Http程序。

2.区别

HttpClient是个很不错的开源框架，封装了访问http的请求头，参数，内容体，响应等等，

HttpURLConnection是java的标准类，什么都没封装，用起来太原始，不方便，比如重访问的自定义，以及一些高级功能等。

3.案例

HttpURLConnection

String urlAddress = "http://192.168.1.102:8080/AndroidServer/login.do";
URL url;
HttpURLConnection uRLConnection;
publicUrlConnectionToServer(){

}//向服务器发送get请求
publicString doGet(String username,String password){
String getUrl = urlAddress + "?username="+username+"&password="+password;
try{
url =newURL(getUrl);
uRLConnection = (HttpURLConnection)url.openConnection();
InputStream is = uRLConnection.getInputStream();
BufferedReader br =newBufferedReader(newInputStreamReader(is));
String response = "";
String readLine =null;
while((readLine =br.readLine()) !=null){
//response = br.readLine();
response = response + readLine;
}
is.close();
br.close();
uRLConnection.disconnect();
returnresponse;
}catch(MalformedURLException e) {
e.printStackTrace();
returnnull;
}catch(IOException e) {
e.printStackTrace();
returnnull;
}
}
 //向服务器发送post请求
publicString doPost(String username,String password){
try{
url =newURL(urlAddress);
uRLConnection = (HttpURLConnection)url.openConnection();
uRLConnection.setDoInput(true);
uRLConnection.setDoOutput(true);
uRLConnection.setRequestMethod("POST");
uRLConnection.setUseCaches(false);
uRLConnection.setInstanceFollowRedirects(false);
uRLConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
uRLConnection.connect();

DataOutputStream out =newDataOutputStream(uRLConnection.getOutputStream());
String content = "username="+username+"&password="+password;
out.writeBytes(content);
out.flush();
out.close();

InputStream is = uRLConnection.getInputStream();
BufferedReader br =newBufferedReader(newInputStreamReader(is));
String response = "";
String readLine =null;
while((readLine =br.readLine()) !=null){
//response = br.readLine();
response = response + readLine;
}
is.close();
br.close();
uRLConnection.disconnect();
returnresponse;
}catch(MalformedURLException e) {
e.printStackTrace();
returnnull;
}catch(IOException e) {
e.printStackTrace();
returnnull;
}
}

HTTPClient

String urlAddress = "http://192.168.1.102:8080/qualityserver/login.do";
publicHttpClientServer(){

}

publicString doGet(String username,String password){
String getUrl = urlAddress + "?username="+username+"&password="+password;
HttpGet httpGet =newHttpGet(getUrl);
HttpParams hp = httpGet.getParams();
hp.getParameter("true");
//hp.
//httpGet.setp
HttpClient hc =newDefaultHttpClient();
try{
HttpResponse ht = hc.execute(httpGet);
if(ht.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
HttpEntity he = ht.getEntity();
InputStream is = he.getContent();
BufferedReader br =newBufferedReader(newInputStreamReader(is));
String response = "";
String readLine =null;
while((readLine =br.readLine()) !=null){
//response = br.readLine();
response = response + readLine;
}
is.close();
br.close();

//String str = EntityUtils.toString(he);
System.out.println("========="+response);
returnresponse;
}else{
return"error";
}
}catch(ClientProtocolException e) {
//TODO Auto-generated catch block
e.printStackTrace();
return"exception";
}catch(IOException e) {
//TODO Auto-generated catch block
e.printStackTrace();
return"exception";
}
}

publicString doPost(String username,String password){
//String getUrl = urlAddress + "?username="+username+"&password="+password;
HttpPost httpPost =newHttpPost(urlAddress);
List params =newArrayList();
NameValuePair pair1 =newBasicNameValuePair("username", username);
NameValuePair pair2 =newBasicNameValuePair("password", password);
params.add(pair1);
params.add(pair2);

HttpEntity he;
try{
he =newUrlEncodedFormEntity(params, "gbk");
httpPost.setEntity(he);

}catch(UnsupportedEncodingException e1) {
//TODO Auto-generated catch block
e1.printStackTrace();
}

HttpClient hc =newDefaultHttpClient();
try{
HttpResponse ht = hc.execute(httpPost);
//连接成功
if(ht.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
HttpEntity het = ht.getEntity();
InputStream is = het.getContent();
BufferedReader br =newBufferedReader(newInputStreamReader(is));
String response = "";
String readLine =null;
while((readLine =br.readLine()) !=null){
//response = br.readLine();
response = response + readLine;
}
is.close();
br.close();

//String str = EntityUtils.toString(he);
System.out.println("=========&&"+response);
returnresponse;
}else{
return"error";
}
}catch(ClientProtocolException e) {
//TODO Auto-generated catch block
e.printStackTrace();
return"exception";
}catch(IOException e) {
//TODO Auto-generated catch block
e.printStackTrace();
return"exception";
}
}

servlet端json转化： 

resp.setContentType("text/json");
resp.setCharacterEncoding("UTF-8");
toDo =newToDo();
List<UserBean> list =newArrayList<UserBean>();
list = toDo.queryUsers(mySession);
String body;

//设定JSON
JSONArray array =newJSONArray();
for(UserBean bean : list)
{
JSONObject obj =newJSONObject();
try
{
obj.put("username", bean.getUserName());
obj.put("password", bean.getPassWord());
}catch(Exception e){}
array.add(obj);
}
pw.write(array.toString());
System.out.println(array.toString());

android端接收：

String urlAddress = "http://192.168.1.102:8080/qualityserver/result.do";
String body =
getContent(urlAddress);
JSONArray array =newJSONArray(body);
for(inti=0;i<array.length();i++)
{
obj = array.getJSONObject(i);
sb.append("用户名:").append(obj.getString("username")).append("\t");
sb.append("密码:").append(obj.getString("password")).append("\n");

HashMap<String, Object> map =newHashMap<String, Object>();
try{
userName = obj.getString("username");
passWord = obj.getString("password");
}catch(JSONException e) {
e.printStackTrace();
}
map.put("username", userName);
map.put("password", passWord);
listItem.add(map);

}

}catch(Exception e) {
//TODO Auto-generated catch block
e.printStackTrace();
}

if(sb!=null)
{
showResult.setText("用户名和密码信息：");
showResult.setTextSize(20);
}else
extracted();

//设置adapter
SimpleAdapter simple =newSimpleAdapter(this,listItem,
android.R.layout.simple_list_item_2,
newString[]{"username","password"},
newint[]{android.R.id.text1,android.R.id.text2});
listResult.setAdapter(simple);

listResult.setOnItemClickListener(newOnItemClickListener() {
@Override
publicvoidonItemClick(AdapterView<?> parent, View view,
intposition,longid) {
intpositionId = (int) (id+1);
Toast.makeText(MainActivity.this, "ID："+positionId, Toast.LENGTH_LONG).show();

}
});
}
privatevoidextracted() {
showResult.setText("没有有效的数据！");
}
//和服务器连接
privateString getContent(String url)throwsException{
StringBuilder sb =newStringBuilder();
HttpClient client =newDefaultHttpClient();
HttpParams httpParams =client.getParams();

HttpConnectionParams.setConnectionTimeout(httpParams, 3000);
HttpConnectionParams.setSoTimeout(httpParams, 5000);
HttpResponse response = client.execute(newHttpGet(url));
HttpEntity entity =response.getEntity();

if(entity !=null){
BufferedReader reader =newBufferedReader(newInputStreamReader
(entity.getContent(),"UTF-8"),8192);
String line =null;
while((line= reader.readLine())!=null){
sb.append(line +"\n");
}
reader.close();
}
returnsb.toString();
}